Dummy messages are used by modules which maintain ordered lists of messages, usually based on message-id. A good example is Mail::Box::Thread::Manager, which detects related messages by scanning the known message headers for references to other messages. As long as the referenced messages are not found inside the mailbox, their place is occupied by a dummy.

Be careful when using modules which may create dummies. Before trying to access the header or body use isDummy() to check if the message is a dummy message.

The message bounce() method forwards a received message off to someone else without modification; you must specified it's new destination. If you have the urge not to specify any destination, you probably are looking for reply(). When you wish to modify the content, use forward().

You may wish to construct a message to be stored in a some kind of folder, but you need to do that in two steps. First, create a normal Mail::Message, and then add it to the folder. During this Mail::Box::addMessage() process, the message will get coerce()-d into the right message type, adding storage information and the like.

Fatal error: the specific package (or one of its superclasses) does not implement this method where it should. This message means that some other related classes do implement this method however the class at hand does not. Probably you should investigate this and probably inform the author of the package.

Dummy messages are place-holders in message threads: the thread detected the existence of the message, because it found the message-id in a Reply-To or References field, however it did not find the header and body of the message yet. Use isDummy() to check whether the thread node returned a dummy or not.